Possibly she didn't explain it properly. If the damned Chinese told the truth in the first instance the entire world wouldn't be in this situation.
There's a distinction when an infection is classed as "airborne" - which is by the aerosol effect, suspended in the air. Most highly infectious diseases like measles and chickenpox gets transmitted through this mechanism.
The other route, for eg like for influenza the transfer is mainly by droplets.... These are larger, do not float easily and fall to ground quickly within 1 - 2 metres.
An airborne disease is more transmissible as a person enters a room and leaves, the aerosols stay afloat for some time in the air and infects the next person who arrives in the room.
The WHO initially insisted that the airborne transmission of SARS-CoV-2 was not possible, possibly believing the Chinese B!@$crap.. Later on they changed their stance saying that this possibly can occur during medical procedures that generate aerosols. Many scientists objected to this statement because with SARS, long ago, WHO insisted that airborne transmission precautions should be observed and eye protection should be used.
The WHO has to take the blame mostly for the failure in the initial response time. Everyone knows why.